pluralyoudaoicibaDictYouDict[plural 词源字典]
plural: [14] Plural is one of a range of English words that go back ultimately to Latin plūs ‘more’, a descendant (like English full and Greek pólus ‘much’, source of the English prefix poly-) of the Indo-European base *plē- ‘full’. This was borrowed into English directly as plus [17], in the sense ‘with the addition of’. Plural comes via Old French plurel from the Latin derivative plūrālis ‘more than one’.

Other related words in English include nonplus [16] (etymologically ‘put in a position where “no more” – Latin nōn plūs – can be done’); pluperfect [16] (a lexicalization of the Latin phrase plūs quam perfectum ‘more than perfect’); and surplus.
=> nonplus, pluperfect, plus, surplus[plural etymology, plural origin, 英语词源]
plural (adj.)youdaoicibaDictYouDict
late 14c., from Old French plurel "more than one" (12c., Modern French pluriel), from Latin pluralis "of or belonging to more than one," from plus (genitive pluris) "more" (see plus). The noun meaning "a plural number" is from late 14c.